A particular problem with known piston rings is that they are not sufficiently resistant to wear. Improved wear resistance has been accomplished through selection of piston ring base materials. In addition, increased wear resistance has been achieved by coating the piston ring base material with a material which has improved wear resistance as compared to the base material. Typical coatings including nitrides, carbides, chromium plating, and ceramic plating. However, known processes for applying these coating are expensive and time consuming.
For example, one known coating approach employs a physical vapor deposition method (PVD) of applying a coating material. PVD utilizes a vacuum chamber in which the coating material is evaporated. In one method, chromium metal cathodes are utilized. The cathodes are vaporized and the chromium becomes nitrided with the introduction of a quantity of nitrogen ions. An electrical potential passed through the articles to be coated ensures that the coating material is deposited on the articles. Although providing acceptable wear resistance, the process is expensive and complex. The PVD process involves long cycle times. It is also unable to provide a layer of coating material that is of sufficient thickness.
The reasons stated above illustrate the need for an improved method for creating wear resistant articles that is more economical, has a shorter cycle time and is capable of producing layers of coating materials that are of sufficient thickness in order to provided extended duty cycles.